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. Author manuscript; available in PMC: 2015 Nov 1.
Published in final edited form as: Neurobiol Dis. 2014 Aug 29;71:345–358. doi: 10.1016/j.nbd.2014.08.027

Figure 3. Characterization of the nigrostriatal dopaminergic pathway of transgenic mice.

Figure 3

(A) Representative images of TH immunostaining in the substantia nigra of R26-LRRK2+/+ and R26-LRRK2+/+/DAT-Cre mice at 12 and 22 months. Scale bar: 100 μm. (B) Representative low power photomicrographs of TH staining from the ventral midbrain of transgenic mice at 22 months. Scale bar: 500 μm. (C) Stereological quantitation of dopaminergic (TH-positive or VMAT-positive) and Nissl-positive neurons in the substantia nigra at 12 and 22 months of R26-LRRK2+/+ and R26-LRRK2+/+/DAT-Cre mice. Bars represent mean ± SEM (n = 5 animals/genotype). Differences were assessed by unpaired, two-tailed Student's t-test, ns, nonsignificant. (D) Representative photomicrographs of TH immunostaining of nerve terminals in the striatum of R26-LRRK2+/+ and R26-LRRK2+/+/DAT-Cre mice at 12 and 22 months. Scale bar: 500 μm. (E) Quantitation of TH immunostaining in the striatum. Data represent the optical density of TH-positive signal (representing dopaminergic fibers) per area of tissue analyzed. Bars represent the mean ± SEM (n ≥ 4 animals/genotype). Differences between groups for each time-point were assessed by unpaired, two-tailed Student's t-test, ns, non-significant. (F) Striatal catecholamine levels were assessed by HPLC with electrochemical detection in 10 month-old homozygous R26-LRRK2+/+ and R26-LRRK2+/+/DAT-Cre mice. The concentration of each biogenic amine is expressed in picograms per μg of protein. The levels of dopamine and its metabolites: 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3 methoxytyramine (3-MT) and dopamine turnover rate ([DOPAC+HVA]/DA) are shown. The concentration of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were also assessed. Bars represent the mean ± SEM (n = 5 animals/genotype). (G) Striatal catecholamine levels measured in 21-24 month-old heterozygous R26-LRRK2+/- and R26-LRRK2+/-/DAT-Cre mice (n = 5 animals/genotype). Comparisons between groups for each age were assessed by unpaired, two-tailed Student's t-test, ns, non-significant.

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